heavy ions

The LHC has just delivered the first pPb (proton-lead) collisions with stable beams of 2013 and CMS is happily running with all sub-detectors on. We are also having common triggers with TOTEM and everything is behaving very well.

The new year brings a new type of collision at the LHC: the accelerator will smash protons and lead nuclei together, allowing CMS and the other LHC experiments to study the cold nuclear matter we expect these collisions to produce.

CMS has published its first paper on proton-lead (pPb) collisions, describing the observation of a phenomenon that was previously seen first in nucleus-nucleus collisions but also detected by CMS in proton-proton (pp) collisions.

In our Universe today, quarks are always bound together by gluons to form "composite" particles such as protons and neutrons. The Quark-Gluon Plasma, or QGP, often described as a soup-like medium, is a hot, dense state in which these quarks and gluons exist freely, unbound.

After only three weeks of heavy-ion running at CERN’s Large Hadron Collider (LHC), the CMS experiment is already yielding new insights into the condition of matter that existed in the very first instants of the Universe’s life, some 13.7 billion years ago.

The CMS experiment at CERN's Large Hadron Collider (LHC) has recorded its first Lead-Lead collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair, marking the start of its heavy ion research programme.